(1) Field of the Invention
The present invention relates to a FAX gateway, a FAX machine, and a FAX transmission system.
(2) Description of the Related Art
Recent technology has introduced a new type of internet facsimile gateways (hereinafter referred to as “Internet FAX machines”) having onramp and offramp functions. An onramp function is capability of receiving facsimile data (hereinafter, “FAX data”) transmitted from a G3 facsimile machine (hereinafter, “FAX machine”) over a public telephone network and then forwarding the FAX data to a terminal on the Internet via Internet mail (hereinafter, “mail”). The offramp function is capability of receiving FAX data contained in a mail (i.e. an e-mail message) transmitted over the Internet and then forwarding the FAX data to a receiving FAX machine over the public telephone network. Hereinafter, an Internet FAX machine having an onramp function is referred to as an “onramp”, and an Internet FAX machine having an offramp function is referred to as an “offramp”.
When an onramp and an offramp are employed as relay (forwarding) stations in FAX transmission from a FAX machine (sending end) to another FAX machine (receiving end) at a remote location, the transmission charge is drastically reduced. This is because in the above FAX transmission, FAX data is transmitted from a sending end sequentially to an onramp, an offramp, and a receiving end. That is to say, the transmission between the onramp and the offramp is carried out over the Internet, which is available under a flat-rate pricing, and transmission over the public telephone network, which is available under usage-based pricing, is carried out over a short distance between the sending end and the onramp as well as between the offramp and the receiving end.
JP unexamined patent application publication 2001-251450, for example, discloses a FAX transmission system via a plurality of relay stations connecting different communication networks that are available under different pricing schemes. This system makes it possible to select an optimum transmission path that keeps the transmission charge to a minimum. In order to make the selection, specifically speaking, the transmission charges for all the possible paths are estimated based on the telephone number area codes of each relay station and of a receiving end, and then a path with the lowest transmission charge is selected.
By employing an onramp and an offramp as the relay stations according to the above technique, a transmission charge for a transmission system with internet FAX machines can be effectively reduced.
With the above system in which an optimum transmission path is selected for a lowest transmission charge, it is desirable that a greater number of onramps and offramps acting as relay stations be located at different locations over a large area. When there are a greater number of relay stations, there are a greater number of selectable transmission paths. Unfortunately, however, in order for performing the transmission and the transmission path selection, it is necessary that each onramp be preliminarily informed of the Internet addresses and telephone numbers of all the offramps.
Conventionally, an administrator of each onramp is obliged to register into the onramp, the Internet addresses and telephone numbers of all the offramps. Consequently, each time an offramp is newly added to the system, the administrator is required to go through a trouble of additionally registering the Internet address and telephone number of the new offramp. Further, there is a need for constantly checking information as to when and where a new offramp is added. This trouble is imposed on each one of the administrators and increases as the number of the offramps increase.
This problem arises also to an administrator of a sending FAX machine. In order to determine whether to perform FAX transmission over a public network or via an onramp and offramp, the sending Fax machine needs to know an offramp closest to a receiving end.